CVE-2025-5270
Published: 27 May 2025
Summary
CVE-2025-5270 is a high-severity Cleartext Transmission of Sensitive Information (CWE-319) vulnerability in Mozilla Firefox. Its CVSS base score is 7.5 (High).
Operationally, ranked at the 37.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-18106
Vulnerability details
In certain cases, SNI could have been sent unencrypted even when encrypted DNS was enabled. This vulnerability was fixed in Firefox 139 and Thunderbird 139.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Role-based training covers secure transmission methods, mitigating cleartext transmission of sensitive data.
By requiring documented security controls for information exchanges, the control reduces the risk of cleartext transmission of sensitive data.
Mapping transmission actions in data flows helps prevent cleartext transmission of sensitive information.
Settings can enforce secure transmission protocols to prevent cleartext transmission of sensitive data.
Policy addresses secure transport and handling of media to avoid cleartext transmission of sensitive information.
Enforces safeguards against cleartext transmission of CUI when data leaves organizational boundaries to external systems.
Explicit controls and continuous oversight on external system services prevent cleartext transmission of sensitive information over provider-managed channels.
Key-establishment procedures specify secure distribution channels that preclude cleartext transmission of key material.